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/*************************************************************************** * _ _ ____ _ * Project ___| | | | _ \| | * / __| | | | |_) | | * | (__| |_| | _ <| |___ * \___|\___/|_| \_\_____| * * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al. * * This software is licensed as described in the file COPYING, which * you should have received as part of this distribution. The terms * are also available at https://curl.se/docs/copyright.html. * * You may opt to use, copy, modify, merge, publish, distribute and/or sell * copies of the Software, and permit persons to whom the Software is * furnished to do so, under the terms of the COPYING file. * * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY * KIND, either express or implied. * * SPDX-License-Identifier: curl * ***************************************************************************/ /* <DESC> * multi socket API usage with epoll and timerfd * </DESC> */ /* Example application source code using the multi socket interface to * download many files at once. * * This example features the same basic functionality as hiperfifo.c does, * but this uses epoll and timerfd instead of libevent. * * Written by Jeff Pohlmeyer, converted to use epoll by Josh Bialkowski Requires a linux system with epoll When running, the program creates the named pipe "hiper.fifo" Whenever there is input into the fifo, the program reads the input as a list of URL's and creates some new easy handles to fetch each URL via the curl_multi "hiper" API. Thus, you can try a single URL: % echo http://www.yahoo.com > hiper.fifo Or a whole bunch of them: % cat my-url-list > hiper.fifo The fifo buffer is handled almost instantly, so you can even add more URL's while the previous requests are still being downloaded. Note: For the sake of simplicity, URL length is limited to 1023 char's ! This is purely a demo app, all retrieved data is simply discarded by the write callback. */ #include <errno.h> #include <fcntl.h> #include <signal.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/epoll.h> #include <sys/stat.h> #include <sys/time.h> #include <sys/timerfd.h> #include <sys/types.h> #include <time.h> #include <unistd.h> #include <curl/curl.h> #define MSG_OUT stdout /* Send info to stdout, change to stderr if you want */ /* Global information, common to all connections */ typedef struct _GlobalInfo { int epfd; /* epoll filedescriptor */ int tfd; /* timer filedescriptor */ int fifofd; /* fifo filedescriptor */ CURLM *multi; int still_running; FILE *input; } GlobalInfo; /* Information associated with a specific easy handle */ typedef struct _ConnInfo { CURL *easy; char *url; GlobalInfo *global; char error[CURL_ERROR_SIZE]; } ConnInfo; /* Information associated with a specific socket */ typedef struct _SockInfo { curl_socket_t sockfd; CURL *easy; int action; long timeout; GlobalInfo *global; } SockInfo; #define mycase(code) \ case code: s = __STRING(code) /* Die if we get a bad CURLMcode somewhere */ static void mcode_or_die(const char *where, CURLMcode code) { if(CURLM_OK != code) { const char *s; switch(code) { mycase(CURLM_BAD_HANDLE); break; mycase(CURLM_BAD_EASY_HANDLE); break; mycase(CURLM_OUT_OF_MEMORY); break; mycase(CURLM_INTERNAL_ERROR); break; mycase(CURLM_UNKNOWN_OPTION); break; mycase(CURLM_LAST); break; default: s = "CURLM_unknown"; break; mycase(CURLM_BAD_SOCKET); fprintf(MSG_OUT, "ERROR: %s returns %s\n", where, s); /* ignore this error */ return; } fprintf(MSG_OUT, "ERROR: %s returns %s\n", where, s); exit(code); } } static void timer_cb(GlobalInfo* g, int revents); /* Update the timer after curl_multi library does it's thing. Curl will * inform us through this callback what it wants the new timeout to be, * after it does some work. */ static int multi_timer_cb(CURLM *multi, long timeout_ms, GlobalInfo *g) { struct itimerspec its; fprintf(MSG_OUT, "multi_timer_cb: Setting timeout to %ld ms\n", timeout_ms); if(timeout_ms > 0) { its.it_interval.tv_sec = 0; its.it_interval.tv_nsec = 0; its.it_value.tv_sec = timeout_ms / 1000; its.it_value.tv_nsec = (timeout_ms % 1000) * 1000 * 1000; } else if(timeout_ms == 0) { /* libcurl wants us to timeout now, however setting both fields of * new_value.it_value to zero disarms the timer. The closest we can * do is to schedule the timer to fire in 1 ns. */ its.it_interval.tv_sec = 0; its.it_interval.tv_nsec = 0; its.it_value.tv_sec = 0; its.it_value.tv_nsec = 1; } else { memset(&its, 0, sizeof(struct itimerspec)); } timerfd_settime(g->tfd, /* flags= */0, &its, NULL); return 0; } /* Check for completed transfers, and remove their easy handles */ static void check_multi_info(GlobalInfo *g) { char *eff_url; CURLMsg *msg; int msgs_left; ConnInfo *conn; CURL *easy; CURLcode res; fprintf(MSG_OUT, "REMAINING: %d\n", g->still_running); while((msg = curl_multi_info_read(g->multi, &msgs_left))) { if(msg->msg == CURLMSG_DONE) { easy = msg->easy_handle; res = msg->data.result; curl_easy_getinfo(easy, CURLINFO_PRIVATE, &conn); curl_easy_getinfo(easy, CURLINFO_EFFECTIVE_URL, &eff_url); fprintf(MSG_OUT, "DONE: %s => (%d) %s\n", eff_url, res, conn->error); curl_multi_remove_handle(g->multi, easy); free(conn->url); curl_easy_cleanup(easy); free(conn); } } } /* Called by libevent when we get action on a multi socket filedescriptor */ static void event_cb(GlobalInfo *g, int fd, int revents) { CURLMcode rc; struct itimerspec its; int action = ((revents & EPOLLIN) ? CURL_CSELECT_IN : 0) | ((revents & EPOLLOUT) ? CURL_CSELECT_OUT : 0); rc = curl_multi_socket_action(g->multi, fd, action, &g->still_running); mcode_or_die("event_cb: curl_multi_socket_action", rc); check_multi_info(g); if(g->still_running <= 0) { fprintf(MSG_OUT, "last transfer done, kill timeout\n"); memset(&its, 0, sizeof(struct itimerspec)); timerfd_settime(g->tfd, 0, &its, NULL); } } /* Called by main loop when our timeout expires */ static void timer_cb(GlobalInfo* g, int revents) { CURLMcode rc; uint64_t count = 0; ssize_t err = 0; err = read(g->tfd, &count, sizeof(uint64_t)); if(err == -1) { /* Note that we may call the timer callback even if the timerfd is not * readable. It's possible that there are multiple events stored in the * epoll buffer (i.e. the timer may have fired multiple times). The * event count is cleared after the first call so future events in the * epoll buffer will fail to read from the timer. */ if(errno == EAGAIN) { fprintf(MSG_OUT, "EAGAIN on tfd %d\n", g->tfd); return; } } if(err != sizeof(uint64_t)) { fprintf(stderr, "read(tfd) == %ld", err); perror("read(tfd)"); } rc = curl_multi_socket_action(g->multi, CURL_SOCKET_TIMEOUT, 0, &g->still_running); mcode_or_die("timer_cb: curl_multi_socket_action", rc); check_multi_info(g); } /* Clean up the SockInfo structure */ static void remsock(SockInfo *f, GlobalInfo* g) { if(f) { if(f->sockfd) { if(epoll_ctl(g->epfd, EPOLL_CTL_DEL, f->sockfd, NULL)) fprintf(stderr, "EPOLL_CTL_DEL failed for fd: %d : %s\n", f->sockfd, strerror(errno)); } free(f); } } /* Assign information to a SockInfo structure */ static void setsock(SockInfo *f, curl_socket_t s, CURL *e, int act, GlobalInfo *g) { struct epoll_event ev; int kind = ((act & CURL_POLL_IN) ? EPOLLIN : 0) | ((act & CURL_POLL_OUT) ? EPOLLOUT : 0); if(f->sockfd) { if(epoll_ctl(g->epfd, EPOLL_CTL_DEL, f->sockfd, NULL)) fprintf(stderr, "EPOLL_CTL_DEL failed for fd: %d : %s\n", f->sockfd, strerror(errno)); } f->sockfd = s; f->action = act; f->easy = e; ev.events = kind; ev.data.fd = s; if(epoll_ctl(g->epfd, EPOLL_CTL_ADD, s, &ev)) fprintf(stderr, "EPOLL_CTL_ADD failed for fd: %d : %s\n", s, strerror(errno)); } /* Initialize a new SockInfo structure */ static void addsock(curl_socket_t s, CURL *easy, int action, GlobalInfo *g) { SockInfo *fdp = (SockInfo*)calloc(1, sizeof(SockInfo)); fdp->global = g; setsock(fdp, s, easy, action, g); curl_multi_assign(g->multi, s, fdp); } /* CURLMOPT_SOCKETFUNCTION */ static int sock_cb(CURL *e, curl_socket_t s, int what, void *cbp, void *sockp) { GlobalInfo *g = (GlobalInfo*) cbp; SockInfo *fdp = (SockInfo*) sockp; const char *whatstr[]={ "none", "IN", "OUT", "INOUT", "REMOVE" }; fprintf(MSG_OUT, "socket callback: s=%d e=%p what=%s ", s, e, whatstr[what]); if(what == CURL_POLL_REMOVE) { fprintf(MSG_OUT, "\n"); remsock(fdp, g); } else { if(!fdp) { fprintf(MSG_OUT, "Adding data: %s\n", whatstr[what]); addsock(s, e, what, g); } else { fprintf(MSG_OUT, "Changing action from %s to %s\n", whatstr[fdp->action], whatstr[what]); setsock(fdp, s, e, what, g); } } return 0; } /* CURLOPT_WRITEFUNCTION */ static size_t write_cb(void *ptr, size_t size, size_t nmemb, void *data) { (void)ptr; (void)data; return size * nmemb; } /* CURLOPT_PROGRESSFUNCTION */ static int prog_cb(void *p, double dltotal, double dlnow, double ult, double uln) { ConnInfo *conn = (ConnInfo *)p; (void)ult; (void)uln; fprintf(MSG_OUT, "Progress: %s (%g/%g)\n", conn->url, dlnow, dltotal); return 0; } /* Create a new easy handle, and add it to the global curl_multi */ static void new_conn(char *url, GlobalInfo *g) { ConnInfo *conn; CURLMcode rc; conn = (ConnInfo*)calloc(1, sizeof(ConnInfo)); conn->error[0]='\0'; conn->easy = curl_easy_init(); if(!conn->easy) { fprintf(MSG_OUT, "curl_easy_init() failed, exiting!\n"); exit(2); } conn->global = g; conn->url = strdup(url); curl_easy_setopt(conn->easy, CURLOPT_URL, conn->url); curl_easy_setopt(conn->easy, CURLOPT_WRITEFUNCTION, write_cb); curl_easy_setopt(conn->easy, CURLOPT_WRITEDATA, conn); curl_easy_setopt(conn->easy, CURLOPT_VERBOSE, 1L); curl_easy_setopt(conn->easy, CURLOPT_ERRORBUFFER, conn->error); curl_easy_setopt(conn->easy, CURLOPT_PRIVATE, conn); curl_easy_setopt(conn->easy, CURLOPT_NOPROGRESS, 0L); curl_easy_setopt(conn->easy, CURLOPT_PROGRESSFUNCTION, prog_cb); curl_easy_setopt(conn->easy, CURLOPT_PROGRESSDATA, conn); curl_easy_setopt(conn->easy, CURLOPT_FOLLOWLOCATION, 1L); curl_easy_setopt(conn->easy, CURLOPT_LOW_SPEED_TIME, 3L); curl_easy_setopt(conn->easy, CURLOPT_LOW_SPEED_LIMIT, 10L); fprintf(MSG_OUT, "Adding easy %p to multi %p (%s)\n", conn->easy, g->multi, url); rc = curl_multi_add_handle(g->multi, conn->easy); mcode_or_die("new_conn: curl_multi_add_handle", rc); /* note that the add_handle() will set a time-out to trigger soon so that the necessary socket_action() call will be called by this app */ } /* This gets called whenever data is received from the fifo */ static void fifo_cb(GlobalInfo* g, int revents) { char s[1024]; long int rv = 0; int n = 0; do { s[0]='\0'; rv = fscanf(g->input, "%1023s%n", s, &n); s[n]='\0'; if(n && s[0]) { new_conn(s, g); /* if we read a URL, go get it! */ } else break; } while(rv != EOF); } /* Create a named pipe and tell libevent to monitor it */ static const char *fifo = "hiper.fifo"; static int init_fifo(GlobalInfo *g) { struct stat st; curl_socket_t sockfd; struct epoll_event epev; fprintf(MSG_OUT, "Creating named pipe \"%s\"\n", fifo); if(lstat (fifo, &st) == 0) { if((st.st_mode & S_IFMT) == S_IFREG) { errno = EEXIST; perror("lstat"); exit(1); } } unlink(fifo); if(mkfifo (fifo, 0600) == -1) { perror("mkfifo"); exit(1); } sockfd = open(fifo, O_RDWR | O_NONBLOCK, 0); if(sockfd == -1) { perror("open"); exit(1); } g->fifofd = sockfd; g->input = fdopen(sockfd, "r"); epev.events = EPOLLIN; epev.data.fd = sockfd; epoll_ctl(g->epfd, EPOLL_CTL_ADD, sockfd, &epev); fprintf(MSG_OUT, "Now, pipe some URL's into > %s\n", fifo); return 0; } static void clean_fifo(GlobalInfo *g) { epoll_ctl(g->epfd, EPOLL_CTL_DEL, g->fifofd, NULL); fclose(g->input); unlink(fifo); } int g_should_exit_ = 0; void sigint_handler(int signo) { g_should_exit_ = 1; } int main(int argc, char **argv) { GlobalInfo g; struct itimerspec its; struct epoll_event ev; struct epoll_event events[10]; (void)argc; (void)argv; g_should_exit_ = 0; signal(SIGINT, sigint_handler); memset(&g, 0, sizeof(GlobalInfo)); g.epfd = epoll_create1(EPOLL_CLOEXEC); if(g.epfd == -1) { perror("epoll_create1 failed"); exit(1); } g.tfd = timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK | TFD_CLOEXEC); if(g.tfd == -1) { perror("timerfd_create failed"); exit(1); } memset(&its, 0, sizeof(struct itimerspec)); its.it_interval.tv_sec = 0; its.it_value.tv_sec = 1; timerfd_settime(g.tfd, 0, &its, NULL); ev.events = EPOLLIN; ev.data.fd = g.tfd; epoll_ctl(g.epfd, EPOLL_CTL_ADD, g.tfd, &ev); init_fifo(&g); g.multi = curl_multi_init(); /* setup the generic multi interface options we want */ curl_multi_setopt(g.multi, CURLMOPT_SOCKETFUNCTION, sock_cb); curl_multi_setopt(g.multi, CURLMOPT_SOCKETDATA, &g); curl_multi_setopt(g.multi, CURLMOPT_TIMERFUNCTION, multi_timer_cb); curl_multi_setopt(g.multi, CURLMOPT_TIMERDATA, &g); /* we do not call any curl_multi_socket*() function yet as we have no handles added! */ fprintf(MSG_OUT, "Entering wait loop\n"); fflush(MSG_OUT); while(!g_should_exit_) { int idx; int err = epoll_wait(g.epfd, events, sizeof(events)/sizeof(struct epoll_event), 10000); if(err == -1) { if(errno == EINTR) { fprintf(MSG_OUT, "note: wait interrupted\n"); continue; } else { perror("epoll_wait"); exit(1); } } for(idx = 0; idx < err; ++idx) { if(events[idx].data.fd == g.fifofd) { fifo_cb(&g, events[idx].events); } else if(events[idx].data.fd == g.tfd) { timer_cb(&g, events[idx].events); } else { event_cb(&g, events[idx].data.fd, events[idx].events); } } } fprintf(MSG_OUT, "Exiting normally.\n"); fflush(MSG_OUT); curl_multi_cleanup(g.multi); clean_fifo(&g); return 0; }